swoole增加了鎖的實現，PHP程式碼中可以很方便地建立一個鎖，用來實現資料同步。swoole_lock類支援5種鎖的型別：

• 檔案鎖 SWOOLE_FILELOCK
• 讀寫鎖 SWOOLE_RWLOCK
• 訊號量 SWOOLE_SEM
• 互斥鎖 SWOOLE_MUTEX
• 自旋鎖 SWOOLE_SPINLOCK

下面我們介紹下其鎖的實現。

static PHP_METHOD(swoole_lock, __construct)
{
    long type = SW_MUTEX;
    char *filelock;
    zend_size_t filelock_len = 0;
    int ret;

    if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "|ls", &type, &filelock, &filelock_len) == FAILURE)
    {
        RETURN_FALSE;
    }

    swLock *lock = SwooleG.memory_pool->alloc(SwooleG.memory_pool, sizeof(swLock));
    if (lock == NULL)
    {
        zend_throw_exception(swoole_exception_class_entry_ptr, "global memory allocation failure.", SW_ERROR_MALLOC_FAIL TSRMLS_CC);
        RETURN_FALSE;
    }

    switch(type)
    {
#ifdef HAVE_RWLOCK
    case SW_RWLOCK:
        ret = swRWLock_create(lock, 1);
        break;
#endif
    case SW_FILELOCK:
        if (filelock_len <= 0)
        {
            zend_throw_exception(swoole_exception_class_entry_ptr, "filelock requires file name of the lock.", SW_ERROR_INVALID_PARAMS TSRMLS_CC);
            RETURN_FALSE;
        }
        int fd;
        if ((fd = open(filelock, O_RDWR | O_CREAT, 0666)) < 0)
        {
            zend_throw_exception_ex(swoole_exception_class_entry_ptr, errno TSRMLS_CC, "open file[%s] failed. Error: %s [%d]", filelock, strerror(errno), errno);
            RETURN_FALSE;
        }
        ret = swFileLock_create(lock, fd);
        break;
    case SW_SEM:
        ret = swSem_create(lock, IPC_PRIVATE);
        break;
#ifdef HAVE_SPINLOCK
    case SW_SPINLOCK:
        ret = swSpinLock_create(lock, 1);
        break;
#endif
    case SW_MUTEX:
    default:
        ret = swMutex_create(lock, 1);
        break;
    }
    if (ret < 0)
    {
        zend_throw_exception(swoole_exception_class_entry_ptr, "failed to create lock.", errno TSRMLS_CC);
        RETURN_FALSE;
    }
    swoole_set_object(getThis(), lock);
    RETURN_TRUE;
}
 

int swRWLock_create(swLock *lock, int use_in_process)
{
    int ret;
    bzero(lock, sizeof(swLock));
    lock->type = SW_RWLOCK;
    pthread_rwlockattr_init(&lock->object.rwlock.attr);
    if (use_in_process == 1)
    {
        pthread_rwlockattr_setpshared(&lock->object.rwlock.attr, PTHREAD_PROCESS_SHARED);
    }
    if ((ret = pthread_rwlock_init(&lock->object.rwlock._lock, &lock->object.rwlock.attr)) < 0)
    {
        return SW_ERR;
    }
    lock->lock_rd = swRWLock_lock_rd;
    lock->lock = swRWLock_lock_rw;
    lock->unlock = swRWLock_unlock;
    lock->trylock = swRWLock_trylock_rw;
    lock->trylock_rd = swRWLock_trylock_rd;
    lock->free = swRWLock_free;
    return SW_OK;
}